Bobcat 743b

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Jamm

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Feb 11, 2019
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Bobcat won't crank. Sometimes it clicks and sometimes it does nothing. Changed relay, starter passed test at auto parts, cleaned battery contacts, replaced ignition switch, battery is fully charged. What else could it be? Thanks
 

craigb93

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Could be corrosion inside the battery cable terminal(s). Probably time for new cables. Be sure to buy at least 2 gage wire cables. Put the felt corrosion washers on too. -Dick
 

walio123

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Could be corrosion inside the battery cable terminal(s). Probably time for new cables. Be sure to buy at least 2 gage wire cables. Put the felt corrosion washers on too. -Dick
I do not remember well, but I think these machines have a solenoid that serves as a pre-starter relay. Do you know how to test the starter by giving it a short between the thin wire and what comes from the battery? If the starter rotates in this way, the problem is somewhere in the ignition key, the wires next to it and / or the pre-starter solenoid.
 
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Jamm

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Could be corrosion inside the battery cable terminal(s). Probably time for new cables. Be sure to buy at least 2 gage wire cables. Put the felt corrosion washers on too. -Dick
Thank you. I just ordered a new starter. If that does not fix it, I will be changing all wires/cables. Thanks again!
 

Tazza

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Thank you. I just ordered a new starter. If that does not fix it, I will be changing all wires/cables. Thanks again!
The easiest way to check the starter is to run +12v to the small pin on the starter, there will be a wire joined to it that should go to the starter relay, if it cranks, the starter is good, if not, the starter is bad.
The connector behind the cab can have corroded pins, if any do fail, you can splice in your own connectors.
 
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Jamm

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The easiest way to check the starter is to run +12v to the small pin on the starter, there will be a wire joined to it that should go to the starter relay, if it cranks, the starter is good, if not, the starter is bad.
The connector behind the cab can have corroded pins, if any do fail, you can splice in your own connectors.
Thanks everyone. I replaced withbnew starter and cleaned all grounds and still just clicks when I try to crank it. What else could it be?
 

walio123

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Thanks everyone. I replaced withbnew starter and cleaned all grounds and still just clicks when I try to crank it. What else could it be?
As Tazza said, try a wire from the battery plus to the thin pin on the starter The starter has to rotate. Are you sure there is no mechanical issue / blocked the engine or pump and just the starter can not turn the engine. Otherwise, if the battery is okay, it should be a broken wire / that of the thin pin on the starter to pre-starter solenoid or relay/. Check what voltage you have on the battery when you try to activate the starter.
 

dabaines

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Jul 31, 2017
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Did you check all the associated fuses? Had the same issue with a jeep I owned years back. Ended up being the wiring that was feeding my fuse box.
 
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Jamm

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Feb 11, 2019
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Did you check all the associated fuses? Had the same issue with a jeep I owned years back. Ended up being the wiring that was feeding my fuse box.
Thanks again everyone! When you say the small pin on starter, you mean the small screw? Anyone know if the 743b has fuses? I looked for them everywhere and didn't find them. I lifted up the whole frame and nothing.
 
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Jamm

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Thanks again everyone! When you say the small pin on starter, you mean the small screw? Anyone know if the 743b has fuses? I looked for them everywhere and didn't find them. I lifted up the whole frame and nothing.
The engine does not seem stuck. The flywheel moves freely. When we tried to "jump" the starter, it just sparks a little nothing else. Even tried that with the new starter. Maybe im not connecting it to the right connections.
 

craigb93

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The engine does not seem stuck. The flywheel moves freely. When we tried to "jump" the starter, it just sparks a little nothing else. Even tried that with the new starter. Maybe im not connecting it to the right connections.
Use Jumper Cables to double the ground from the (-) battery post and the engine as a first test. If it starts replace the (-) cable. You may not be able to see corrosion inside the terminal ends. If still no go use the other jumper cable to double the wire from the (+) battery post to the big post on the starter. Then use a small wire to connect the (+) jumper cable momentarily to the small post on the starter. If it starts now replace the (+) Battery Cable. As was said up thread these machines use a small solenoid to engage the starter. If you can hear it click with the key it is probably good. If it is suspect check it with a test light while an assistant turns the key. -Dick
 

walio123

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Use Jumper Cables to double the ground from the (-) battery post and the engine as a first test. If it starts replace the (-) cable. You may not be able to see corrosion inside the terminal ends. If still no go use the other jumper cable to double the wire from the (+) battery post to the big post on the starter. Then use a small wire to connect the (+) jumper cable momentarily to the small post on the starter. If it starts now replace the (+) Battery Cable. As was said up thread these machines use a small solenoid to engage the starter. If you can hear it click with the key it is probably good. If it is suspect check it with a test light while an assistant turns the key. -Dick
Are you sure the battery is fully charged? The proper connection of the starter test described it as craigb93.The starter must rotate.The only thing if it does not spin is a bad battery Remove the battery terminals, clear them with sandpaper, disconnect the other end of the wires and clean the cable shoes too.There must be 2 ground (or more) wires from the battery. One iс attached on main frame , the other on the engine housing.Probably the old starter is good.
 

Tazza

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Are you sure the battery is fully charged? The proper connection of the starter test described it as craigb93.The starter must rotate.The only thing if it does not spin is a bad battery Remove the battery terminals, clear them with sandpaper, disconnect the other end of the wires and clean the cable shoes too.There must be 2 ground (or more) wires from the battery. One iс attached on main frame , the other on the engine housing.Probably the old starter is good.
Hopefully this image works
SolenodeWiring.jpg

The red wire is where your battery +ve cable should run, the yellow/cream wire is the one to run +12v into and should make the starter spin. If it doesn't on either starter, it has to be a bad cable or battery.
 
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Jamm

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Feb 11, 2019
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Hopefully this image works

The red wire is where your battery +ve cable should run, the yellow/cream wire is the one to run +12v into and should make the starter spin. If it doesn't on either starter, it has to be a bad cable or battery.
Thank you. I have not even tried anything else yet because I have been trying to get job done first. Im going to charge the old battery first and seen if it turms over. I also just noticed it was leaking hydraulic fluid from the arm. Not sure if that would have anything to do with it. Will post update. Thanks to all who have replied.
 

Tazza

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Thank you. I have not even tried anything else yet because I have been trying to get job done first. Im going to charge the old battery first and seen if it turms over. I also just noticed it was leaking hydraulic fluid from the arm. Not sure if that would have anything to do with it. Will post update. Thanks to all who have replied.
leaking oil won't stop it starting, but it is something that should ab addressed when time allows.
Hopefully a new battery solves the issue.
 

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